JP2001215333A - Semitransmissive semireflective polarizing element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semitransmissive and semireflective polarizing element capable of giving a semitransmissive and semireflective liquid crystal display device ensuring reflective brightness equal to, and transmissive brightness brighter than, the conventional one. SOLUTION: The semitransmissive and semireflective polarizing element 71 is characterized by having a dichroic polarizing element 41, a reflective polarizing element 43 and a semitransmissive and semireflective layer 47 laminated in such a way that the transmission axes of the dichroic polarizing element and the reflective polarizing elements are located in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a transflective polarizing element.

[0002]

2. Description of the Related Art Liquid crystal display devices are used in various fields because of their small size and light weight. Such a liquid crystal display device can be used as a reflective liquid crystal display device in a bright environment, and can be used as a transmissive liquid crystal display device illuminated by a built-in back light source in a dark environment. The device is widely used. A conventional transflective liquid crystal display device (10) will be described with reference to FIG. The liquid crystal cell (20) is composed of two opposing transparent electrodes, that is, a transparent electrode (21) on the rear side and a transparent electrode (22) on the front side, and a liquid crystal layer (23) sandwiched between the transparent electrodes (21, 22). It is composed of The liquid crystal cell (2
Optical elements such as a dichroic polarizing element (31) and a retardation element (32) are arranged on the front surface of the liquid crystal cell (2).
A polarized light source device (11) is arranged on the back of the device (0). The liquid crystal cell (20) and the polarized light source device (11) may be arranged via a rear-side retardation element (42). The polarized light source device (11) is provided at a position facing the liquid crystal cell (20), at a position facing the liquid crystal cell (20), a transflective polarizing element (1) composed of a dichroic polarizing element (41) and a transflective transflective layer (46).
2), a light guide plate (52) arranged on the back surface, a light source (51) arranged on the end or the back surface of the light guide plate, and a reflection plate (53) arranged on the back surface of the light guide plate. Consists of

The transflective polarizing element (12) is a laminated film of a transparent or translucent resin body and a polarizing layer in which a light diffusing substance is dispersed in the translucent resin body (for example, a transflective polarizing element). Japanese Unexamined Patent Publication (Kokai) No. 55-46707) and those using a pearl pigment dispersed uniformly in a transparent substance and utilizing reflection on the pearl pigment surface (for example, Japanese Patent Application Laid-Open No. 55-84975) are used.

[0004]

SUMMARY OF THE INVENTION The present invention provides a semi-transmissive-semi-reflective polarizing element capable of providing a transflective liquid crystal display device having a reflection luminance equivalent to that of the prior art and having a higher transmission luminance than the conventional one. Is what you do.

[0005]

That is, the first aspect of the present invention is as follows.
In the invention, the dichroic polarizing element, the reflective polarizing element, and the transflective layer are laminated such that the transmission axis of the dichroic polarizing element and the transmission axis of the reflective polarizing element are in the same direction. And a semi-transmissive and semi-reflective polarizing element.

As the dichroic polarizing element, an iodine polarizing film or a dye polarizing film can be used.
A light diffusion layer may be laminated on at least one surface of the dichroic polarizing element.

[0007] The reflective polarizing element includes a multilayer laminate of two or more polymer films, a polymer film in which two or more polymers form an islands-in-the-sea structure or a film made of cholesteric liquid crystal and a quarter. It is preferable to use a wave plate and a laminated one.

[0008] The semi-transmissive semi-reflective layer, the slow axis or fast axis and the transmission axis of the dichroic polarizing element are in the same direction,
And / or the transflective layer has an in-plane retardation value of 30n.
m or less. The transflective layer is preferably a layer in which a metal thin film is formed on the surface of a polymer film or a layer in which flaky reflective particles are dispersed in a pressure-sensitive adhesive. As the flaky reflective particles, particles obtained by forming a layer made of a metal oxide on the surface of mica pieces can be preferably used.

According to a second aspect of the present invention, there is provided a polarized light source apparatus comprising the transflective polarizing element of the present invention, a light source, and a reflector laminated in this order, or a semi-transparent light source device of the present invention. A polarized light source device comprising a transflective polarizing element, a light guide plate having a light source disposed at an end, and a reflective plate laminated in this order.

A third invention of the present invention is a transflective liquid crystal display device characterized in that the polarized light source device of the present invention, a liquid crystal cell and a dichroic polarizing element are arranged in this order. . Here, one or more retardation elements may be interposed between at least one of the transflective polarizing element and the liquid crystal cell and between the liquid crystal cell and the dichroic polarizing element.
Further, a light diffusion layer may be sandwiched between the liquid crystal cell and the dichroic polarizing element.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. The “semi-transmissive and semi-reflective polarizing element” (71) of the present invention comprises a dichroic polarizing element (41), a reflective polarizing element (43) and a transflective semi-reflective layer (47). The transmission axis of the element (41) and the reflective polarizing element (43)
Are laminated so that their transmission axes are in the same direction. Here, the “transmission axis” of the dichroic polarization element and the “transmission axis” of the reflection type polarization element mean that the transmittance becomes maximum when polarized light in a specific vibration direction is incident from the perpendicular direction of the polarization element. Say the direction.

The transmission axis of the dichroic polarization element and the transmission axis of the reflection type polarization element are set in the same direction so that polarized light passing through the reflection type polarization element can also pass through the dichroic polarization element effectively. In order to Therefore, it is most preferable that the transmission axes of the two types of polarizing elements are completely in the same direction. However, if the loss of light due to the intersection of the transmission axes is within a negligible range, it is regarded as substantially “the same direction”. Can be.
Specifically, if the crossing angle is 10 ° or less, it can be used without any problem.

In the present invention, the order of laminating the dichroic polarizing element, the reflective polarizing element, and the transflective layer is as follows.
"Dichroic polarizing element (41), reflective polarizing element (43),
And the order of the transflective layer (47) ”(FIG. 1), or“ the dichroic polarizing element (41), the transflective layer (4) ”.
7), and the order of the reflective polarizing element (43) ”(FIG. 2). Further, when the in-plane retardation value of the transflective layer is large or when the slow axis direction is not constant, the order is “dichroic polarizing element, reflective polarizing element, transflective layer”. More preferably, when the in-plane retardation value of the reflective polarizing element is large, the order of the dichroic polarizing element, the transflective layer and the reflective polarizing element is more preferable. Further, two or more transflective layers of the same type or different types may be used, and may be laminated in the order of “dichroic polarizing element, transflective semireflective layer, reflective polarizing element, transflective semireflective layer”. May be used.

In the present invention, the “dichroic polarizing element”
It transmits polarized light in a specific vibration direction and absorbs polarized light orthogonal to the polarized light. Such a “dichroic polarizing element”
For example, a known iodine-based polarizing film or dye-based polarizing film can be used. The “iodine-based polarizing film” is a film in which iodine is adsorbed on a stretched polyvinyl alcohol film, and the “dye-based polarizing film” is a film in which a dichroic dye is adsorbed on a stretched polyvinyl alcohol film. In order to improve the durability, it is preferable that one or both sides of the polarizing film is coated with a polymer film. As the material of the polymer to be coated for this protection, cellulose diacetate, cellulose triacetate, polyethylene terephthalate, norbornene resin and the like can be used. Further, as a polymer film to be coated for protection, a reflective polarizing element or a transflective layer described later can be used.
Although the thickness of the dichroic polarizing element is not particularly limited, when the polarizing element of the present invention is used for a liquid crystal display device or the like, the thinner one is preferable, and at least 1 mm or less, more preferably 0.2 mm or less.
mm or less.

The “reflection type polarizing element” in the present invention includes:
It transmits polarized light in a specific vibration direction and reflects polarized light orthogonal to the polarized light. Such a “reflective polarizing element”
For example, a reflective polarizing element using a difference in the reflectance of a polarization component due to a Brewster angle (for example, Japanese Patent Application Laid-Open No. 6-508449), a reflective polarizing element using a selective reflection characteristic of cholesteric liquid crystal ( For example, Japanese Patent Application Laid-Open No. 3-45906 discloses a reflective polarizing element on which a fine metal linear pattern is applied (for example, Japanese Patent Application Laid-Open No. 2-3081).
No. 06), a reflective polarizing element (for example, Japanese Patent Application Laid-Open No. 9-506837) in which two kinds of polymer films are laminated and utilizing the anisotropy of the reflectance due to the refractive index anisotropy. (See, for example, US Pat. No. 5,825,543), which has a sea-island structure and utilizes the anisotropy of the refractive index due to the refractive index anisotropy. A reflective polarizing element utilizing the anisotropy of reflectivity due to anisotropy (for example, Japanese Patent Application Laid-Open No. H11-509014), a method in which inorganic particles are dispersed in a polymer film, and a difference in reflectivity based on a difference in scattering ability depending on the size. A reflective polarizing element utilizing anisotropy (for example, JP-A-9-297204) can be used. The thickness of these reflective polarizing elements is not particularly limited, but when the transflective polarizing element of the present invention is used for a liquid crystal display element or the like, the thinner is preferable,
It is preferably at least 1 mm or less, more preferably 0.2 mm or less. Therefore, a reflection type polarizing element utilizing the selective reflection characteristic of the cholesteric liquid crystal, two types of polymer films are laminated, and a reflection type polarizing element utilizing the anisotropy of the reflectance due to the refractive index anisotropy, a polymer film. A reflective polarizing element having a sea-island structure and utilizing the anisotropy of the reflectance due to the refractive index anisotropy is particularly preferable for reducing the thickness of the polarizing element of the present invention. However, since the semi-transmissive and semi-reflective polarizing element according to the present invention functions for linearly polarized light, when a reflective polarizing element utilizing selective reflection characteristics of cholesteric liquid crystal is used, circularly polarized light is converted to linearly polarized light. It is necessary to laminate the optical elements to form a reflective polarizing element. The optical element is generally called a quarter wave plate.

In order to obtain a transflective liquid crystal display device having a bright display screen, it is preferable to reduce the light absorption of the transflective polarizing element of the present invention. for that reason,
It is preferable to increase the transmittance of the dichroic polarizing element used for the transflective polarizing element of the present invention. In general, the higher the transmittance of the dichroic polarizing element, the lower the degree of polarization,
Therefore, when used in a liquid crystal display device, the contrast of an image is reduced, but in the transflective polarizing element of the present invention, a dichroic polarizing element and a reflective polarizing element are used in combination, When the degree of polarization of the reflective polarizing element is high, the transmittance of the dichroic polarizing element can be increased and the degree of polarization can be decreased in a desired range.

In the present invention, the “semi-transmissive semi-reflective layer”
It transmits a part of the incident light beam and reflects the remaining part. Here, with respect to all the incident light beams, the remaining portion which is not transmitted and reflected is absorbed by the semi-transmissive semi-reflective layer and cannot be used effectively, so that the absorption is preferably as small as possible. As this “semi-transmissive semi-reflective layer”, a transparent or translucent resin body in which particles or cavities having a different refractive index from the resin body are dispersed, or a transparent or translucent resin body having a refractive index A layer formed by forming a cured film of light or thermosetting resin in which different particles or cavities are dispersed, a layer formed by attaching a metal thin film to a transparent or translucent resin body, or a multilayer of two or more polymer thin films Those formed by lamination can be used alone or by laminating two or more layers. When two or more layers are stacked, the same layer may be used or different layers may be used.

Here, the material of the "resin body" used for the transflective layer in the present invention is not particularly limited. Polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride resins, vinyl acetate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cyclic polyolefin resins such as norbornene, polycarbonate resins, polysulfone resins, polyethers Synthetic polymers such as sulfone resins, polyarylate resins, polyvinyl alcohol resins, polyurethane resins, polyacrylate resins, and polymethacrylate resins, and natural polymers such as cellulose resins such as cellulose diacetate and cellulose triacetate Polymers can be used. Further, the “resin body” may be a pressure-sensitive adhesive. In this case, acrylate-based pressure-sensitive adhesive, methacrylate-based pressure-sensitive adhesive, vinyl chloride-based pressure-sensitive adhesive, synthetic rubber-based pressure-sensitive adhesive, natural rubber-based adhesive,
A silicone adhesive or the like can be used. Among these pressure-sensitive adhesives, acrylate-based pressure-sensitive adhesives are one of the preferred resin bodies in terms of handling properties and durability.
Known light or thermosetting resins can be used. For example, a compound having a reactive double bond such as an acrylate group, a methacrylate group, or an aryl group, and a compound having a ring-opening condensable reactive group such as an epoxy group can be given. When performing light or heat curing, an additive such as a photopolymerization initiator, a heat stabilizer, an ultraviolet stabilizer, or a leveling agent can be added to the light or thermosetting resin. A known method can be used as a method for performing light or heat curing.

The material of "particles having different refractive indices" which can be used for the transflective layer in the present invention is not particularly limited, and any of organic particles and inorganic particles can be used. Examples of the organic particles include particles of a polymer such as a polyolefin resin such as polystyrene, polyethylene, and polypropylene; a polymer such as a polymethacrylate resin and a polyacrylate resin; and a cross-linked polymer that is cross-linked. Furthermore, selected from ethylene, propylene, styrene, methyl methacrylate, benzoguanamine, formaldehyde, melamine, butadiene, etc.
Copolymers obtained by copolymerizing more than one kind can also be used. Examples of the inorganic particles include particles of silica, silicone, titanium oxide, mica, glass, talc, hydrotalcite, aluminum oxide, and the like. The hue is preferably colorless or white, but colored fine particles may be used to provide decorativeness. In addition, in order to improve the reflectance of light rays by the particles, the surface of the particles may be coated with a high refractive index substance. At the time of coating, it is preferable to adjust the coating thickness so that the high refractive index material coating becomes a reflection increasing film. As the high refractive index substance, a metal oxide such as titanium oxide can be suitably used. The shape of the particles is not particularly limited, and may be spherical, spindle-shaped, or amorphous. However, in order to effectively provide the reflection performance, the particles are preferably in the form of scales. Furthermore, the scaly particles (62)
However, as shown in the schematic cross-sectional view of FIG. 3, it is preferable that the resin body (61) is oriented parallel to the surface of the resin body (61). When the particle size is too small, light scattering performance is not exhibited, and when too large, the display quality is deteriorated when used in a liquid crystal display device.
m or less. The amount of the fine particles to be added can be appropriately set according to the desired reflectance. Usually, it is 0.01 to 50 parts by weight based on 100 parts by weight of the resin body to be dispersed.

The metal used for the "metal thin film" which can be used for the transflective layer in the present invention is not particularly limited, but aluminum and silver are preferably used.
The film thickness is adjusted according to desired transmission performance / reflection performance. In other words, if the emphasis is placed on increasing the transmissivity of the transflective layer, and thus aiming at lowering the reflectivity, the thinner metal thin film can maintain the higher transmissivity and maintain the higher reflectivity. Lower. Conversely, if the emphasis is placed on increasing the reflectance, and therefore the aim is to lower the transmittance, then by increasing the thickness of the metal thin film, the transmittance can be reduced and the reflectance can be increased. The range is usually 1
A thickness of not less than nm and not more than 100 μm, and more preferably not less than 10 nm and not more than 1 μm is suitably used. As a method for attaching a metal thin film to the transparent polymer film, a vapor deposition method or a sputtering method is suitably used, but a film obtained by thinly rolling a metal may be bonded with an adhesive including a pressure-sensitive type.
When attaching the metal thin film to the resin body, a known undercoat layer may be provided for improving the adhesion, or a known overcoat layer may be provided for protecting the metal thin film.

The material of the "polymer thin film" that can be used for the transflective layer in the present invention is not particularly limited, and the same materials that can be used for the "resin body" described above can be used. A method of imparting reflective performance by laminating polymer thin films in multiple layers is described, for example, in J. Mol. A. "POLYMER ENGINEERING AND" by RADFORD et al.
SCIENCE ", page 216, No. 13 (1973).

In the present invention, it is preferable that the slow axis or the fast axis of the transflective layer and the transmission axis of the dichroic polarizing element are in the same direction. Alternatively, the in-plane retardation value of the transflective layer is preferably 30 nm or less. Here, the “slow axis” or the “fast axis” of the semi-transmissive semi-reflective layer refers to the direction in which the refractive index in the plane of the semi-transmissive semi-reflective layer becomes maximum and the direction in which the refractive index becomes minimum, respectively. . The limitation of these axis angles and in-plane retardation values is to prevent the polarization state of the polarized light passing through the dichroic polarizing element or the reflective polarizing element from being affected by the transflective layer. It is. Therefore, the slow axis or fast axis of the transflective layer,
It is most preferable that the transmission axis of the dichroic polarizing element is strictly coincident with the dichroic polarizing element.However, even if there is some difference, as long as the influence on the polarization state is small, it can be considered that the transmission directions are substantially the same. . If the difference in the axis angle is 10 ° or less, the influence on the polarization state is usually small, and it can be used without any problem. The in-plane retardation value of the transflective layer is most preferably 0 nm.
If it is 0 nm or less, it can be normally used without any problem. These limitations on the axis angle and the in-plane retardation value are particularly effective when the transflective layer is disposed between the dichroic polarizing element and the reflective polarizing element.

When the light diffusing property of the transflective polarizing element according to the present invention is low, a light diffusing layer can be laminated on at least one surface of the dichroic polarizing element. As the “light diffusion layer”, a transparent or translucent resin body in which particles having a different refractive index from the resin body are dispersed, or a particle having a different refractive index in a transparent or translucent resin body is dispersed. What formed the cured film of the light or thermosetting resin which was made can be used.

The "resin body" and "cured film of light or thermosetting resin" used for the light diffusion layer are not particularly limited, and known ones can be used. For example, the substances exemplified as the “resin body” and the “cured film of a light or thermosetting resin” that can be used in the above-described transflective layer can be used.

The material of the “particles having different refractive indexes” used for the light diffusion layer is not particularly limited, and any of organic particles and inorganic particles can be used. Examples of the organic particles include particles of a polymer such as a polyolefin resin such as polystyrene, polyethylene, and polypropylene, and a polymer such as an acrylic resin, and may be a cross-linked polymer. Furthermore, ethylene, propylene, styrene, methyl methacrylate, benzoguanamine, formaldehyde,
A copolymer obtained by copolymerizing two or more selected from melamine, butadiene and the like can also be used. Examples of the inorganic particles include particles of silica, silicone, titanium oxide, glass, aluminum oxide, and the like. The hue is preferably colorless or white, but colored fine particles may be used to provide decorativeness. "Light scattering layer"
The shape of the particles in is not particularly limited, but since the “light scattering layer” preferably functions as a forward scattering element, a spherical, spindle-like or cubic shape is suitably used. When the particle size is too small, light scattering performance is not exhibited, and when the particle size is too large, display quality deteriorates when used in a liquid crystal display device. Therefore, the particle size is preferably 0.1 μm or more and 50 μm or less. The amount of the fine particles to be added can be appropriately set according to the desired reflectance. Usually, it is 0.01 to 50 parts by weight based on 100 parts by weight of the resin body to be dispersed.

When laminating the light diffusion layer, the slow axis or the fast axis of the light diffusion layer and the transmission axis of the dichroic polarizing element are substantially in the same direction, or the in-plane of the light diffusion layer is Preferably, the retardation value is 30 nm or less.

When the transflective polarizing element of the present invention is used in a liquid crystal display device, there may be a case where brightness unevenness reflects the shape of the light source of the backlighting device. In such a case, as shown in FIG. 4 or 5, two transflective layers can be used. Here, as the two transflective layers, the same kind of layer or different kinds of layers may be used.

When the transflective polarizing element of the present invention is laminated, in order to reduce the loss of light due to the interface with air, an air layer is not inserted between the constituent elements or layers. It is preferable that the pressure-sensitive adhesive is sandwiched and closely laminated. Known pressure-sensitive adhesives can be used, for example, acrylate-based pressure-sensitive adhesives, methacrylate-based pressure-sensitive adhesives, vinyl chloride-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, natural rubber-based adhesives, and silicone-based pressure-sensitive adhesives An adhesive or the like can be used. Among these pressure-sensitive adhesives, acrylate-based pressure-sensitive adhesives are particularly preferable in terms of handling properties and durability.

One embodiment of the “polarized light source device” of the present invention is as follows.
The transflective polarizing element of the present invention, the surface of the transflective polarizing element opposite to the dichroic polarizing element, a light source,
The reflectors are arranged in this order. Here, at least one diffusion sheet may be arranged between the transflective polarizing element and the light source.

Another form of the "polarized light source device" of the present invention is as follows.
A transflective polarizing element of the present invention, a light guide plate having a light source disposed at an end, and a reflecting plate, on the surface of the transflective polarizing element opposite to the dichroic polarizing element, They are arranged in this order. Here, at least one diffusion sheet, and / or between the transflective polarizing element and the light guide plate.
Alternatively, at least one lens sheet may be arranged. .

The "light source" in the present invention is not particularly limited, and those used in known polarized light source devices and liquid crystal display devices can be used. That is, a cold cathode tube, a light emitting diode, an inorganic or organic EL lamp, or the like can be used.

The "reflecting plate" in the present invention is not particularly limited, and those used in known polarized light source devices and liquid crystal display devices can be used. That is, a white plastic sheet having a cavity formed therein, a plastic sheet having a surface coated with a white pigment such as titanium oxide or zinc white, a plastic sheet obtained by laminating two or more plastic films having different refractive indices, aluminum, A metal sheet such as silver can be used. These sheets may be mirror-finished or roughened. The material of the "plastic sheet" is not particularly limited, and polyethylene, polypropylene, polyvinyl chloride,
Polyethylene terephthalate, polyethylene naphthalate, polycarbonate, norbornene, polyurethane,
Polyacrylate, polymethyl methacrylate and the like can be used.

The "light guide plate" in the present invention is one which takes in light emitted from a light source and functions as a planar light-emitting body, and a known light guide can be used. As such a “light guide plate”, for example, a light guide plate made of a plastic sheet or a glass plate, which has been subjected to unevenness processing, white dot printing processing, and hologram processing on the back side can be used. Here, the material of the “plastic sheet” is not particularly limited,
Polycarbonate, norbornene, polymethyl methacrylate and the like are preferably used.

The “diffusion sheet” in the present invention is a sheet that scatters and transmits incident light, and has a total light transmittance of 60%.
This is an optical element having a haze ratio of 10% or more.
Here, the higher the total light transmittance, the better. That is, the total light transmittance is more preferably 80% or more. Such a “diffusion sheet” is not particularly limited, but for example, a plastic sheet or a glass plate which has been subjected to surface roughening treatment, or a material in which cavities or particles are added inside can be used. Here, the material of the “plastic sheet” is not particularly limited, but polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, norbornene,
Polyurethane, polyacrylate, polymethyl methacrylate and the like can be used. The surface roughening treatment is not particularly limited, and examples thereof include a method of pressing by sand blasting or embossing roll, and a method of applying a mixture of plastic particles, glass particles, silicon particles, and the like to a resin on the surface. it can.

The "lens sheet" in the present invention is for condensing light emitted from a light source, and a known material can be used. As such a “lens sheet”, for example, a lens in which many fine prisms are formed on a plastic sheet, or a microlens array in which convex lenses and concave lenses are spread are used.

The "transflective transflective liquid crystal display device" of the present invention.
Is a device in which a polarized light source device of the present invention and a liquid crystal cell and a dichroic polarizing element are arranged in this order on the side opposite to the reflector of the polarized light source device. Here, if necessary, a phase difference element or a light diffusion element for performing optical compensation between the polarized light source device and the liquid crystal cell and / or between the liquid crystal cell and the dichroic polarizing element. May be interposed. Further, it is preferable that these members are closely adhered by a pressure-sensitive adhesive.

[0037]

The embodiments of the present invention will be described below with reference to examples, but the present invention is not limited to the examples.

The evaluation method is as follows. (1) Total light transmittance and haze ratio A haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.) was obtained by bonding a transflective polarizing element to a glass plate via a pressure-sensitive adhesive. The arrangement was such that the measurement light was incident from the glass plate side, and the total light transmittance and the haze rate were measured. (2) Visibility Corrected Transmittance A Nicol prism was installed in the sample chamber measurement light emission light section of the Shimadzu self-recording spectrophotometer UV-2200 (manufactured by Shimadzu Corporation) so as to emit polarized light in a specific vibration direction. . Then, on the optical path of the polarized light, the one that is bonded to the glass plate via a pressure-sensitive adhesive on the dichroic polarizing element side of the semi-transmissive and semi-reflective polarizing element, The light is arranged so as to be incident, and is arranged in a direction in which the transmittance of the polarized light is maximized.
100 nm, and the transmittance T (T
D, λ). Next, the direction of these polarizing elements is set to 90.
After rotation, the measurement was performed again from the incident wavelength of 400 nm to 700 nm in increments of 10 nm, and the transmittance T (MD, λ) at each wavelength λ on the axis orthogonal to the polarization transmission axis was determined. Using the average value of these transmittances, a stimulus value Y value in a 2 ° visual field of a C light source was calculated according to JIS Z8701, and was set as a luminosity corrected transmittance.

(3) Visibility correction polarization degree Using the transmittance measured in (2), the parallel transmittance T (parallel, λ) at each wavelength λ is calculated by the equation (1) to obtain the orthogonal transmittance T (parallel, λ) at each wavelength λ. The transmittance and T (orthogonal, λ) were determined by equation (2). T (parallel, λ) = (T (TD, λ) ² + T (MD, λ) ² ) / 2 (1) T (orthogonal, λ) = T (TD, λ) × T (MD, λ) (2 A stimulus value Y value in a C light source 2 ° visual field is calculated from these transmittances in accordance with JIS Z8701, and a luminosity correction parallel transmittance Y (parallel) and a luminosity correction orthogonal transmittance Y are respectively obtained.
(Orthogonal). Using these, the visibility correction polarization degree P
y was determined by equation (3). Py = ((Y (parallel) −Y (orthogonal)) / (Y (parallel) + Y (orthogonal))) ^1/2 (3)

(4) Visibility Corrected Reflectance An absolute reflectance measuring device was installed on a Shimadzu self-recording spectrophotometer UV-3100PC (manufactured by Shimadzu Corporation), and a transflective polarizing element was bonded to a glass plate. It is arranged so that the measurement light is incident from the glass plate side, and the incident wavelength range 380
In order to remove the influence of the polarization component of the measurement light, the reflectance of the measurement is measured from nm to 780 nm in increments of 5 nm. In order to remove the influence of the polarization component of the measurement light, the direction of the transflective polarizing element is set in two directions, one direction and the direction orthogonal thereto. Then, the reflectance at each wavelength was determined by averaging. Then, the stimulus value Y value in a 2 ° visual field was calculated using “color measurement software” attached to the spectrophotometer, and the calculated stimulus value was defined as a luminosity correction reflectance.

(5) Transmission Luminance A light source (51) composed of a cold-cathode tube is arranged at the end, and a light guide plate (52) with white dot printing (54) on the back surface, and a reflection made of foamed PET on the back surface. The plate (53) was provided with a diffusion sheet (55) on the front side to produce a light source device (57) schematically shown in FIG. A semi-transmissive and semi-reflective polarizing element (71) is further placed thereon via a pressure-sensitive adhesive so that the dichroic polarizing element (41) comes to the glass plate (61) side.
A polarized light source device (72) was produced by arranging a glass plate (61) having a thickness of m and bonded thereto. A photometric unit (81) connected to a spectrophotometer light receiving unit by an optical fiber (82) was arranged in a direction perpendicular to the polarized light source device (72). The emission line spectra corresponding to “blue”, “green”, and “red” of the cold cathode tube (51) used as the light source of the polarized light source device (72) are 435 nm, 545 nm, and 6 nm, respectively.
Since it was 12 nm, the transmitted and received light intensity at these wavelengths was measured. (6) Reflection luminance Round loupe ENV-B-2 (Otsuka Optical Co., Ltd.)
The loupe was used as an annular external light source device. Ring fluorescent lamp (84) of the round loupe,
It was arranged horizontally at a height of 25 cm from the pedestal.
On the pedestal was placed black paper (85) to absorb extra light. In a dark room, an illuminometer was placed on the black paper, and the input power was adjusted so that the illuminance of the annular fluorescent lamp was 1000 lux. Then, instead of the illuminometer, a transflective and semi-reflective polarizing element bonded to a glass plate is arranged at the center so that the glass plate becomes an incident light surface, and a luminance meter BM-7 installed above. The reflection luminance of the sample was measured according to (83). The dichroic polarizing elements include Sumikaran SR1862A and SR1872, which are commercially available iodine-based polarizing films.
A and SR1882A (both manufactured by Sumitomo Chemical Co., Ltd.) were used. Table 1 shows the luminosity corrected transmittance and the luminosity corrected polarization degree of these dichroic polarizing elements.

A commercially available DBEF (manufactured by Sumitomo 3M Limited) was used as the reflective polarizing element. Table 1 shows the luminosity correction transmittance and the luminosity correction polarization degree. The transflective semi-reflective layer is a commercially available AS-0, which is a laminated integrated product of a transflective transflective layer made of a pressure-sensitive adhesive in which pearl mica is dispersed and a transflective transflective layer made of a polyethylene terephthalate film.
11 and AS-031 (both manufactured by Sumitomo Chemical Co., Ltd.) were used. However, in the study, a transflective semi-reflective layer composed of a pressure-sensitive adhesive in which pearl mica was dispersed and a transflective semi-reflective layer composed of a polyethylene terephthalate film were used separately.

As shown schematically in FIG. 8, a commercially available lens sheet (for example, BEF (trade name) manufactured by Sumitomo 3M Limited) (56) is arranged on the back of the transflective polarizing element (71). And a light guide plate (52) made of polymethyl methacrylate in which a commercially available diffusion sheet (for example, light up made by Kimoto Co., Ltd.) (55) is arranged, and a light source (51) made of a cold cathode tube is arranged at the end. ) And a reflector (53) made of a foamed white polyethylene terephthalate film on the back,
A polarized light source device (74) can be manufactured.

A phase difference element (for example, Sumikalite (trade name) manufactured by Sumitomo Chemical Co., Ltd.) (42) is arranged on the front surface of the polarized light source device (74) if necessary, and a liquid crystal cell (20) is further provided on the front surface. And a front-side retardation element (32), if necessary, and a front-side dichroic polarizing element (31), so that the transflective liquid crystal display device (75) can be provided. Can be made.

Comparative Example 1 Dichroic Polarizing Element SR1862
Conventionally, a pressure-sensitive adhesive in which AS-011 pearl mica is dispersed as a semi-transmissive semi-reflective layer is tightly laminated on A, and a polyethylene terephthalate film of AS-011 is further tightly laminated as a semi-transmissive semi-reflective layer. Was manufactured. Table 3 shows the total light transmittance, the haze ratio, and the luminosity corrected reflectance of the transflective polarizing element.

[Example 1] Dichroic polarizing element SR1862
A, a reflective polarizing element DBEF was tightly laminated via a pressure-sensitive adhesive such that the transmission axes of the dichroic polarizing element and the reflective polarizing element coincided with each other. Table 2 shows the luminosity-corrected transmittance and the luminosity-corrected polarization degree of the laminated integrated product. Furthermore, AS-0 as a transflective layer is provided on the reflective polarizing element side of the laminated integrated product.
A semi-transmissive semi-reflective polarizing element was produced by tightly laminating a pressure-sensitive adhesive in which 11 pearl mica were dispersed, and further laminating tightly an AS-011 polyethylene terephthalate film as a semi-transmissive semi-reflective layer. Table 3 shows the total light transmittance, the haze ratio, and the luminosity corrected reflectance of the transflective polarizing element. Table 4 shows a transmission light receiving intensity ratio and a reflection luminance ratio of the transflective polarizing element with respect to Comparative Example 1. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. The brightness of the screen is almost the same, and when used as a "transmission type", a brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

Example 2 SR187 was used for the dichroic polarizing element.
The same evaluation as in Example 1 was performed except that 2A was used. Table 2 shows the luminosity-corrected transmittance and the luminosity-corrected polarization degree, Table 3 shows the total light transmittance, the haze ratio, and the luminosity-corrected reflectance, and Table 4 shows the transmitted light-receiving intensity ratio and the reflection luminance ratio with respect to Comparative Example 1. Show. From these results, a transflective liquid crystal display using the transflective polarizing element,
When used as a “reflective type”, the screen brightness is almost the same as that using a conventional transflective type polarizing element, and when used as a “transmissive type”, the conventional transflective type is used. A screen brighter than that using a polarizable element can be provided.

Example 3 SR188 was used for the dichroic polarizing element.
The same evaluation as in Example 1 was performed except that 2A was used. Table 2 shows the luminosity-corrected transmittance and the luminosity-corrected polarization degree, Table 3 shows the total light transmittance, the haze ratio, and the luminosity-corrected reflectance, and Table 4 shows the transmitted light-receiving intensity ratio and the reflection luminance ratio with respect to Comparative Example 1. Show. From these results, a transflective liquid crystal display using the transflective polarizing element,
When used as a “reflective type”, the screen brightness is almost the same as that using a conventional transflective type polarizing element, and when used as a “transmissive type”, the conventional transflective type is used. A screen brighter than that using a polarizable element can be provided.

Example 4 Dichroic Polarizing Element SR1862
A, a reflective polarizing element DBEF was tightly laminated via a pressure-sensitive adhesive such that the transmission axes of the dichroic polarizing element and the reflective polarizing element coincided with each other. Table 2 shows the luminosity-corrected transmittance and the luminosity-corrected polarization degree of the laminated integrated product. Furthermore, AS-0 as a transflective layer is provided on the reflective polarizing element side of the laminated integrated product.
A semi-transmissive, semi-reflective polarizing element was produced by tightly laminating a pressure-sensitive adhesive in which 11 pearl mica were dispersed and further laminating tightly an AS-031 polyethylene terephthalate film as a semi-transmissive semi-reflective layer. Table 4 shows a transmission light receiving intensity ratio and a reflection luminance ratio of the transflective polarizing element with respect to Comparative Example 1. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. Although the brightness of the screen is slightly reduced, when used as a "transmission type",
A brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

Comparative Example 2 Dichroic Polarizing Element SR1862
Conventionally, A is laminated with a pressure-sensitive adhesive in which AS-031 pearl mica is dispersed as a semi-transmissive semi-reflective layer and further laminated with an AS-031 polyethylene terephthalate film as a semi-transmissive semi-reflective layer. Was manufactured. Table 3 shows the total light transmittance, the haze ratio, and the luminosity corrected reflectance of the transflective polarizing element.

[Embodiment 5] Dichroic polarizing element SR1862
A, a reflective polarizing element DBEF is closely adhered and laminated via a pressure-sensitive adhesive such that the transmission axes of the dichroic polarizing element and the reflective polarizing element coincide with each other, and AS-0 is formed as a semi-transmissive semi-reflective layer.
A semi-transmissive semi-reflective polarizing element was produced by tightly laminating a pressure-sensitive adhesive in which 31 pearl mica were dispersed, and further laminating tightly an AS-031 polyethylene terephthalate film as a semi-transmissive semi-reflective layer. Table 3 shows the total light transmittance, the haze ratio, and the luminosity corrected reflectance of the transflective polarizing element. Table 5 shows a transmission light reception intensity ratio and a reflection luminance ratio of the transflective polarizing element with respect to Comparative Example 2. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. The brightness of the screen is almost the same, and when used as a "transmission type", a brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

Example 6 SR187 was used as a dichroic polarizing element.
The same evaluation as in Example 4 was performed except that 2A was used. Table 3 shows the total light transmittance, the haze ratio, and the luminosity-corrected reflectance, and Table 5 shows the transmitted light-receiving intensity ratio and the reflection luminance ratio with respect to Comparative Example 2. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. The brightness of the screen is almost the same, and when used as a "transmission type", a brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

[Example 7] SR188 was used for the dichroic polarizing element.
The same evaluation as in Example 4 was performed except that 2A was used. Table 3 shows the total light transmittance, the haze ratio, and the luminosity-corrected reflectance, and Table 5 shows the transmitted light-receiving intensity ratio and the reflection luminance ratio with respect to Comparative Example 2. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. The brightness of the screen is almost the same, and when used as a "transmission type", a brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

[Embodiment 8] Dichroic polarizing element SR1862
A, a pressure-sensitive adhesive in which AS-031 pearl mica is dispersed as a semi-transmissive semi-reflective layer is closely adhered and laminated, and furthermore, the reflective polarizing element DBEF is connected to the dichroic polarizing element and the reflective polarizing element. A semi-transmissive and semi-reflective polarizing element was produced by closely contacting and laminating them so as to match each other. Table 3 shows the total light transmittance, the haze ratio, and the luminosity corrected reflectance of the transflective polarizing element. Table 5 shows a transmission light reception intensity ratio and a reflection luminance ratio of the transflective polarizing element with respect to Comparative Example 2. From these results, the transflective liquid crystal display device using the transflective polarizing element is, when used as a “reflection type”, compared with a conventional transflective polarizing element using a conventional transflective polarizing element. As a result, the brightness of the screen is slightly increased, and when used as a “transmission type”, a brighter screen can be provided as compared with a conventional one using a transflective polarizing element.

[0055]

By using the transflective polarizing element of the present invention, a brighter screen can be obtained with the same power consumption as the conventional one, while having the same reflection luminance as the conventional one. Therefore, if the screen luminance is the same as the conventional one, the power consumption can be reduced, and the liquid crystal display device can be used for a long time with one charge of the battery. Alternatively, the capacity of the battery can be reduced, and the size and weight of the liquid crystal display device can be reduced.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

[Table 5]

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of a transflective polarizing element according to the present invention.

FIG. 2 is a schematic sectional view showing an example of the transflective polarizing element of the present invention.

FIG. 3 is a schematic cross-sectional view showing an alignment state of flaky reflective particles in a resin body.

FIG. 4 is a schematic cross-sectional view showing an example of a transflective polarizing element of the present invention.

FIG. 5 is a schematic cross-sectional view showing one example of a transflective polarizing element of the present invention.

FIG. 6 is a schematic cross-sectional view illustrating a configuration of a transmission luminance evaluation device in an example.

FIG. 7 is a schematic cross-sectional view illustrating a configuration of a reflection luminance evaluation device in an example.

FIG. 8 is a schematic sectional view showing an example of a transflective liquid crystal display device of the present invention.

FIG. 9 is a schematic sectional view showing an example of a conventional transflective liquid crystal display device.

[Explanation of symbols]

 10: Conventional transflective liquid crystal display device 11: Conventional polarized light source device 12: Conventional transflective semi-reflective polarizing element 20: Liquid crystal cell 21: Back transparent electrode 22: Front transparent electrode 23: Liquid crystal layer 31: Front dichroic polarizing element 32: Front dichroic element 41: Back dichroic polarizing element 42: Rear dichroic element 43: Reflective polarizing element 45: Pressure sensitive adhesive 46: Conventional semi-transmissive Semi-reflective film 47: Semi-transmissive semi-reflective layer 48: Semi-transmissive semi-reflective layer 51: Light source 52: Light guide plate 53: Reflector plate 54: White dot printing 55: Diffusion sheet 56: Lens sheet 57: Light source device 61: Resin body 62: Scale-like reflective particles 71: Transflective transflective polarizing element 72: Polarized light source device 74: Polarized light source device 75: Transflective transflective liquid crystal display device 81: Photometry unit 82: Optical fiber Bar 83: Luminance meter 84: Fluorescent lamp 85: Black paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 520 G02F 1/1335 520 1/13357 1/13363 1/13363 1/1335 530 F term (Reference ) 2H042 BA02 BA20 DA01 DA02 DA04 DA06 DA11 DA21 DA22 DB01 DC02 DC07 DD04 DE04 2H049 BA07 BA26 BA27 BA42 BB03 BB33 BB43 BB63 BB65 BC22 2H088 EA47 GA03 HA17 HA18 HA21 HA25 HA28 MA02 2H091 FA08Z FAZZ FA14Z FAZZ FA14 GA16 LA17

Claims (16)

[Claims] 1. A dichroic polarizing element, a reflective polarizing element, and a transflective layer are laminated such that the transmission axis of the dichroic polarizing element and the transmission axis of the reflective polarizing element are in the same direction. A transflective polarizing element comprising: 2. The transflective polarizing element according to claim 1, wherein the dichroic polarizing element is an iodine polarizing film or a dye polarizing film. 3. The transflective polarizing element according to claim 1, wherein a light diffusing layer is laminated on at least one surface of the dichroic polarizing element. 4. The transflective polarizing element according to claim 1, wherein the reflective polarizing element is a multilayer laminate of two or more polymer films. 5. The transflective polarizing element according to claim 1, wherein the reflective polarizing element is a polymer film in which two or more kinds of polymers form a sea-island structure. 6. A transflective polarizing element according to claim 1, wherein the reflective polarizing element is formed by laminating and integrating a film made of cholesteric liquid crystal and a quarter-wave plate. element. 7. The semi-transmissive semi-reflection according to claim 1, wherein the slow axis or the fast axis of the semi-transmissive semi-reflective layer and the transmission axis of the dichroic polarizing element are in the same direction. Polarizer. 8. An in-plane retardation value of the transflective layer is 30 nm.
The transflective polarizing element according to claim 1, wherein: 9. The semi-transmissive semi-reflective layer is a layer in which a metal thin film is formed on the surface of a polymer film.
The transflective polarizing element according to any one of the above. 10. The transflective polarized light according to claim 1, wherein the transflective layer is a layer in which flaky reflective particles are dispersed in a pressure-sensitive adhesive. element. 11. The flake-like reflective particles are particles in which a layer made of a metal oxide is formed on the surface of a mica piece.
0. The transflective polarizing element according to item 0. 12. A polarized light source device comprising the transflective polarizing element according to claim 1, a light source, and a reflector laminated in this order. 13. A transflective polarizing element according to claim 1, a light guide plate having a light source disposed at an end thereof, and a reflecting plate laminated in this order. Characterized polarized light source device. 14. A transflective liquid crystal display device comprising the polarized light source device according to claim 12 or 13, a liquid crystal cell and a dichroic polarizing element arranged in this order. 15. A device according to claim 1, wherein one or more phase difference elements are sandwiched between at least one of the transflective polarizing element and the liquid crystal cell and between the liquid crystal cell and the dichroic polarizing element.
5. The transflective liquid crystal display device according to 4. 16. The transflective liquid crystal display device according to claim 14, wherein a light diffusion layer is sandwiched between the liquid crystal cell and the dichroic polarizing element.